The Gillibrand bill would be paid for by a payroll tax of about $1.61 a week for a “typical worker,” the campaign says. Clinton, however, wants the wealthiest Americans to pay for it. She has pledged to not raise taxes on the middle class.

Before Sanders’ discussion on the topic, Clinton’s senior policy advisor Ann O’Leary said in a Thursday statement “this is not a new fight for Hillary.”

“Hillary believes we can do this without asking working people to pay for it,” she said.